Solve for $x$ and $y$ using substitution. ${x-4y = 6}$ ${x = 5y+7}$
Answer: Since $x$ has already been solved for, substitute $5y+7$ for $x$ in the first equation. ${(5y+7)}{- 4y = 6}$ Simplify and solve for $y$ $5y+7 - 4y = 6$ $y+7 = 6$ $y+7{-7} = 6{-7}$ ${y = -1}$ Now that you know ${y = -1}$ , plug it back into $\thinspace {x = 5y+7}\thinspace$ to find $x$ ${x = 5}{(-1)}{ + 7}$ $x = -5 + 7$ ${x = 2}$ You can also plug ${y = -1}$ into $\thinspace {x-4y = 6}\thinspace$ and get the same answer for $x$ : ${x - 4}{(-1)}{= 6}$ ${x = 2}$